Ladies and Gentlemen of the class of 19999, B.C.:
Wear a loin cloth.
If I could offer you one tip for the future, it would be to wear a loin cloth. The long-term effects of outer coverings have been proven by previous generations, whereas the rest of my advice has no basis whatsoever, they are simply thoughts coming from my meandering Cro-Magnon skull. I will dispense this advice now.
Enjoy the power and beauty of the club. Oh, never mind, you wouldn't understand. Only when you are old and feeble, and can no longer swing a club with power and finesse will you fully appreciate the gift you have now. Trust me, in 10 years when you're dying at age 32, you'll look back at these days and marvel at the potential you had whenever you swung your club.
Don't worry about the future. Or worry, but know that worrying is as effective as hunting a woolly mammoth with a twig. The real troubles in your life are apt to be things that never crossed your mind, the kind of ice age that blinds you at 4 p.m. on some idle Tuesday.
Do one thing everyday that causes a genetic mutation.
Develop opposable thumbs.
On your birthday, paint on your cave wall. Not just men with spears, but what you truly feel. Flowers. Small mammals. Blazing meteors.
Don't feel guilty if you don't know what to do with your life. Some people will evolve into Neanderthals, others will simply fade away over time. Some will learn to use tools, others will discover fire. Others will be the first burn victim at the first ad hoc ICU.
Keep your old love letters. Throw away those heavy stone bank tablets.
Maybe you'll marry, maybe you won't. Maybe you'll have 10 children. Maybe seven of them will die before they're a year old. Maybe you'll get divorced at 23. Maybe you'll dance the funky bison at your 10th wedding anniversary. Maybe you'll unwittingly marry your first cousin through the curse of a small gene pool and suffer from a recessive trait like straight hair or five fingers.
Whatever you do, don't try to congratulate yourself too much. Language is a slow process requiring much development. Content yourself with grunting. There is nothing wrong with grunting.
Don't look too closely at reflecting pools. Don't over-examine your protruding jaw and underdeveloped forehead. This will only make you feel ugly.
Reinvent the wheel.
Worry. Soon, Pangea will split up.
Accept certain unalienable truths: rocks fall when released; there are 20 amino acids; smoking can cause cancer; the cube of the distance from a satellite to the sun is related to the square of the satellite's rotation period around the sun.
Get plenty of calcium. Be kind to your outer extremities. You'll miss them when they fall off after a harsh winter.
Be careful whose advice you take, but be patient with those who supply it. Advice is a form of shoebox-sized propaganda. It plays on the need to dispense the wisdom you lacked when you were young to those who need it least, those who must learn for themselves. It undermines the entire process we went through to gain the knowledge we have.
In the end, though, you are the only one who counts. No one else's hokey faux-platitudes can ever fully sum up a complete life experience.
But trust me on the loin cloth.